Manufacture of wool-like cellulosic material



l atenterl hug. do

WILLl til HARRISON, 01E MANCHESTER, lENGlLhND.

'UFAUTURE U "WOOL-LIKE GELLUJLOSIU MATERT.

Tito Drawing. Application filed January 26, 1927, Serial No. lfitflfil, and in Great Britain February 12,

This invention relates to the manufacture I of wool-like cellulosic material.

hill

The object of this invention is to produce a material from a cellulosic fibre which has more of the properties of wool in relation to elasticity, warmth and shrinking properties than materials produced by hitherto known processes and which at the same time will possess the necessary stability to retain its properties.

llt is known that cotton, and particularly unbleached cotton when treated with nitric acid of certain concentration acquires some of the characteristics of wool and also that sulphuric acid under certain conditions pro duces a similar effect but neither of the processes gives a material which can be shrunk except by treatment with caustic soda of a concentration of over 12%. Furthermore neither process is easy to carry out in practice because of the known tendering action of acids on cellulose and neither process produces a product having any great similarity to wool.

llt is also known that by subjecting a cellu losic material such as cotton either with or without the application of tension to the combined action of caustic soda and carbon disulphide, a Xanthate can be produced which is insoluble in water but which like the soluble xanthate known as viscose is very unstable. lit is readily decomposed by dilute solutions of mineral acids, by strong oxidizing agents such as hypochlorites, by heat and also spontaneously when in contact with water or alkaline solutions. For example,

during the drying of materials containing or consisting'ot this insoluble Xanthate by the customary 'methods used in the textile industry decomposition takes place and the material acquires a yellow color from the icy-products formed.

The production of this unstable and insoluble Xanthat-e has been described in a number of previous patents e. g.AshWell, British Patent No. 19,012 of 1901; Cross a Bevan, British Patent No. 126,174.; Lilienfeld, British Patent No. 216,476; Lilienfeld, British Patent No.' 216,477 Aykroyd & Hrais, German Patent No. 6850/1829 and Joliot, German Patent No. 322,047.

Gn account however of the unstability of the product it has not hitherto been found possible to use it commercially.

already combined with the cellulose to convert itinto a compound which will not be decomposed by dilute solutions of mineral acids, by heat or by long standing in contact with water and which being reactive imparts shrinking properties to the cellulosic material.

Tn carrying out the invention a cellulosic fibre such as cotton, either with or without the application ottension at any stage during the process, is subjected to the combined action of caustic alk'alies or alkaline sulphides or mixtures of the same and carbon disulphide. The amount olf carbon disulphide and the time of treatment are so arranged that the product obtained is insoluble or only sparingly or partially soluble in water. The carbon disulphide may be applied in vapour form or in solution in an inert solvent such as benzene, either before or after, but preferably after treatment with the alkaline solution or may be applied simultaneously with the alkaline solution. in the form of an emulsion suspension or colloidal solution inthe alkaline solution. The caustic soda may also be applied both before and after the treatment with carbon disulphide and the material may or may not be subjected to tension during either or both of these treatments with caustic soda or of subsequent washing. lBy application or tension particularly during the washing process a lustre similar to that of wool may be im parted.

Generally speaking the amount or carbon disulphide and/or the time of treatment are to be raised in an inverse ratio to the concentration and/or amount of alkaline solution applied to the cellulosic fibre.

The unstable insoluble xanthate produced by the above process or by any other process is then washed with water or with salt solution to remove the by-products, this washing process being performed rapidly.

so as to prevent appreciable decomposition -which does not completely split oti' the carbon disulphide already combined with the cellulose.

Of these mild oxidizing agents nitrous acid lends itself admirably to the process since it is much cheaper than tcrricyanides or iodine and its action is considerably more rapid than air even in presence of catalysts. The nitrogen oxides formed in the reaction may colour the cellulosic material but this colour is readily removed by means of sulphurous acid.

By reason of this mild oxidizing process the unstable "xanthate is converted into another compound, most probably by the union of two of the carbon disulphide residues, which is not decomposed by dilute solutions of mineral'acids nor by heat nor by long standing in contact with water and which being reactive imparts shrinking properties to the cellulosic material.

The following example, to which it is to be understood that the invention is in no way limited illustrates how'the process may be carried out Unbleached cotton preferably in the form of yarn is impregnated with caustic soda of 15% strength the excess being removed in a hydroextractor. The impregnated yarn is then placed in a closed chamber and subjected to the action of carbondisulphide in vapour form and 15% of the weight of the cellulose for a period depending on the amount of carbon disulphide'used usually less than four hours.

The insoluble xanthate formed is washedfree from the yellow by-products with water" these pro erties can be imparted can he yaried wit in extremely wide limits by varying the conditions of treatment at the several stages in the process.

- The new products have dyeing properties very ditlcrcnt from those of ordinary cellulosic fibres, having strong atlinity for basic colours and for certain acid colours particularly those of the sulphonatcd basic type.

The dyeing and other properties can be modified further by making use of the reactivity of the compounds produced by this process towards many organic compounds particularly those of basic character of which compounds containing one or more basic nitrogen groupings are (X{tll'l[)l(S. Aniline benzylamine and 1)lienylhydruzinc are particularly reactive and impart atlinity for other acid colours. Soluble derivatives of anhydroformaldehyde aniline may also be applied to improve the ailinity towards ordinary acid colours of the azo type.

Shrinking of the materials can be produced in a variety of ways such as for ex ample by treating the material with ammonia, sodium sulphide or sodium sulphite preferably in the presence of an alkali or with caustic soda of less than 12% strength.

with or without the addition of ammonia sodium sulphide or sulphite.

The process may be applied to ccllulosic fibers such as cotton, linen, ramie, jute and the like or to cellulosic artificial silks, in the form of fibers, yarns or fabrics but of these, yarns offer advantages in so far that a large variety of new effects can be secured in fabrics by making'use of the altered dyeing properties more particularly by using yarns subjected to different degrees of treatment by the process and because the shrinle ing properties canbe utilizcd to give special properties as regards clasticity, warmth and general handle of the result fabrics.

What I claim as my invention and desire to protect by Lettcrs atent is:-

1. Process for the production of woollike cellulosic material consisting in subjecting the unstable insoluble xanthate, formed by the combined action of a caustic alkali or alkaline sulphide or any mixture of these and carbon disulphide on ccllulosic material, to the action of a mild oxidizing agent which does not completely split oil the carbon disulphide previously combined with the cellulose and which converts the unstable insoluble xanthate into a stable compound.

2. Process for the production of wool like cellulosic material which consists in subjecting the unstable insoluble xanthate,

.formed by the combined action of a caustic alkali or alkaline sulphide or any mixture of these and carbon disulphide on ccllulosic material, to .the action ot nitrous acid,

which converts the unstable insoluble xan-' thate into a stable compound.

3. Process for the production of woolhke cellulosic material which consists in subjecting the unstable insoluble xanthate,

Hit)

ueeo oai tormecl by the eornbineol action of a eaustie allrali or alkaline sulpbiele or any mixture at these ancl carbon olisulpbitle on cellulosie material, to the action of nitrous acirl ancl acetic aoicl, Whichconverts the unstable insoluble arantliate into a stable compouncl,

4t. Woollilre eellulosie material prorluoedl by subjecting the unstable insoluble tan axm' l 5 Wool-hire eellulosie material proolueecl by subjecting the unstable insoluble tliate to the action oil nitrous aeiol.

lln testimony Wliereoit l have hereunto my loandl. 'Wlillillilrlilul ltlllllEi-lmtlltjtlblw. 

